Disposable pull-on diapers have been well known and successfully commercialized. For example, WO 2006/017718 describes a disposable pull-on diaper having a waist opening and two leg openings. The disposable pull-on diaper comprises an absorbent main body and a ring-like elastic belt. The absorbent main body comprises a liquid pervious topsheet, a liquid impervious backsheet, and an absorbent core disposed therebetween. The ring-like elastic belt comprises a belt substrate layer and a belt elastic material joined to the belt substrate layer. The two longitudinal ends of the absorbent body are joined to the ring-like elastic belt in front and back.
Tape-type and pull-on type diapers are the two main types of disposable diapers. Pull-on diapers are recently increasing popularity due to the convenience of applying a pull-on diapers on an infant. When putting a tape-type diaper on an infant, to achieve comfortable fit, a care-taker needs to pay close attention to the positioning of the diaper relative to the infant's body and the stretching level applied in taping diaper's ears to its landing zone. In contrast, pull-on diapers have predefined waist opening and leg openings and thus allows a care-taker to put the diapers on an infant's body by simply inserting the infant's legs in the leg opening and pulling the diaper up over the waist. So far, pull-on diapers have mainly been successful in large and medium sized diapers. However, there is much area for improvement for pull-on diapers in small size.
Small-sized diapers are intended for use on infants having body weight of less than 8 kilograms. Infants of this body size are typically less than 10 months old and in average, they sleep about 13-18 hours a day. For them, diapers are more likely changed while they are sleeping. Hence, it is desirable that the small-sized diapers can be applied onto the infants with ease so that their sleep will not be disturbed. Furthermore, small-sized infants typically have thighs of greater circumference but smaller waist than medium and large sized infants. In addition, the legs of small-sized infants are usually not in a straightened state, but are more often in a curved position which requires a wider waist opening to put the diaper through the curved legs. Hence, to simply downsize medium and large sized pull-on diapers to small size would not provide desirable waist and leg fit as well as the desirable ease of application.
Also, it has been found that currently commercialized small-sized pull-on diapers are not stretchable enough to be applied with ease. Some have also been found not to fit well in legs. Therefore, there is still a need for a small-sized disposable pull-on diaper which can be applied with ease and can fit the waist and legs of a wearer better.